Ceph Terminology

Block Device

A Ceph component that provides access to Ceph storage as a thinly provisioned block device. When an application writes to a Block Device, Ceph implements data redundancy and enhances I/O performance by replicating and striping data across the Ceph Storage Cluster.

Also known as a RADOS Block Device or RBD.

BlueStore

The default storage backend for Ceph OSDs.

Ceph Client

A host that can contains the Ceph Command Line Interface libraries to configure and deploy a Ceph Storage Cluster. A Ceph Client need not be a member node of a Ceph Storage Cluster.

Also known as administration node, or admin node.

Ceph Manager (ceph-mgr)

A Ceph component used by external monitoring tools to report on nodes in a Ceph Storage Cluster. Runs on the same nodes that run Ceph Monitor on Ceph Storage Cluster nodes

Also known as a Manager.

Ceph Monitor (ceph-mon)

A Ceph component used for tracking active and failed nodes in a Ceph Storage Cluster.

Also known as a Monitor or MON.

Ceph OSD (ceph-osd)

A Ceph component that provides access to an OSD.

Also known as a Ceph OSD Daemon.

Ceph Storage Cluster

A Ceph component that stores MON and OSD data across cluster nodes.

Also known as a Ceph Object Store, RADOS Cluster, or Reliable Autonomic Distributed Object Store.

Node

A host system that is a member of a Ceph Storage Cluster.

Object Gateway

A Ceph component that provides a RESTful gateway that can use the Amazon S3 and OpenStack Swift compatible APIs to present OSD data to Ceph Clients, OpenStack, and Swift clients. An Object Gateway is configured on a node of a Ceph Storage Cluster.

Also known as a RADOS Gateway or RGW.

Object Storage Device (OSD)

Storage on a physical device or logical unit (LUN). The default management system is BlueStore. Oracle recommends data on an OSD is configured as a Btrfs file system to take advantage of its snapshot features. However, XFS and BlueStore can also be used.